Telephony.



M. L. JOHNSON TELEPHONY.

APPLIOATIQN FILED AUG. 10, 1911.

Patented Oct 7, 1913.

\ 4 2' SEEMS-SHEET 1.

& 1,075,251

T O OTHER TELEPHONE 5 TAT! 0 N5 nwavro/z MORTON JOHNS 0N ATTORNEY M. L. JOHNSON.

TELEPHONY.

APPLIUATION FILED AUG. 10, 1911.-

1 $375,257,, Patented Oct. 7, 1913.

2 SHEETS-SHEET 2.

M MflRToN .L. JOHNSON WW ATTORNEY of exchanges" as IINI'EED STATES PATENT OFFIQE.

MORTON In. JOHNSON, OF CHICAGO, ILLINOIS, ASSIGNOR T0 CORWIN TELEPHONE MAN- UFACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONY.

Specification of Letters Patent.

Patented Oct. *7, 1913.

Application filed August 10, 1911. Serial No. 643,337.

To all whom it may concern:

Be it known that I, MORTON L. J onrzson, citizen of the United States, residing at Chicago, in the county. of Cook and State of Illinois, have invented a certain new and useful Improvement in Telephony, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to telephone exchange systems from which some party telephone lines extend.

My invention has for its general object the provision of improved means whereby a party line which has been taken for use is guarded against the intrusion of the other statioiis uponthe same line.

My invention is of particular service in connection with those exchanges where means are provided for automatically effecting the extension of telephone lines but I do not desire to be limited to this class features thereof are of service inconnect-ion with other exchanges.

Reference may be had to my co-pending application Serial No. (328,777, filed May 22, 1911, the system disclosed in my present application having in its preferred form, features that are broadly covered by said co-pending application.

I will explain my invention more fully by reference to the accompanying drawings showing the preferred embodiment thereof and in which Figure 1 is a view illustrating a party telephone line with a plurality of stations thereupon; Fig. 2 is'a view illustrating another party telephone line, but one station being shown, howeveryand Fig. 3 illustrates automatic exchange mechanism taking'part in connecting the lines shown in Figs. 1 and 2, the three figures being read together by placing the top of the sheet containing Figs. 1 and 2 in register with the bottom of the sheet containing Fig. 3.

Similar parts of the equipment illustrated at each of the telephone stations, of Figs. 1 and 2 are given similar characters of reference.

Each of the telephone lines extends from the exchange in two limbs 1, 2 and, in the embodiment of the invention illustrated, is normally connected at its two sides with the poles of a battery 3, each side 1 being nordo not think it necessary mally grounded and connected through the ground with the positive pole of the battery 3, the negative pole of which is normally connected ,with each side 2 of the lines.

Mechanism is provided at the exchange for reversing the current applied to a party telephone line, when such line is a calling line, after a party at one of the telephone stations upon such line takes the line for use, the then reversed so that the side 1 is charged from the negative pole of the battery and the side 2 is charged from the positive pole of the battery. The apparatus by which the battery 3 is reversed, and which is illustrated in Fig. 3, is familiar to those skilled in the art of automatic telephony andwill be later more fully referred to.

I have shown in Fig. 1 four party line stations A, B, C, D, though I do not limit myself to the number of stations that are connected with the party line. As the invention is illustrated the equipments at all of the four stations are identical except, if desired, the signal receivers at the diiferent stations which may be of harmonic type to respond to wave form current of different periodicities to be selectively impressed upon the line at the exchange. The signal receivers may be alike, if desired, in which event code signals should be employed. I to illustrate the manner in which the signaling current is applied to the signal receivers as such does not form an essential part of my present invention.

Similar parts at the different stations will be given similar characters of reference, one station being specifically described.

I have illustrated a well known type of switching mechanism at each station for operating the selecting mechanism at the exchange, this mechanism including a spring winding finger ring or dial 4, employed intermittently to separate the contacts 5 and 6 by mechanism which need not be described specifically. A polarized relay 7 is employed at each station, this relay having an armature switch 8 whose armature member is directly connected with the side 2 ofthe telephone line and whosenormally disengaged stationary contact member is normally connected with the side 1 of the telephone line through the telephone receiver 9, telephone transmitter 10, the winding of a open bridge between the sides of the telephone line, this bridge being established when the receiver thereat is removed from its switch hook12, the bridge circuit then established being traceable from the side 1 the telephone bridge.

of the telephone line, through the winding of the relay 7, the then engaged contacts 13 and 14, to the side 2 of the telephone line. If the station at which the receiver is re moved is a calling station or is a called station, the battery 3 has normal relation with the line so that current therefrom will cause the polarized relay 7 to operate and thereby close the contacts of the armature S of said' polarized relay 7 to establish a circuit through the magnet 11 which may be traced from the side 1 of the telephone line through the contacts 5, 6, the winding of magnet 11, the transmitter 10, the telephone receiver 9, contacts of the armature switch 8, to the side 2 of thevtelep'hone line, .the magnet 11 being thereupon energized to withdraw its armature from its normal mechanical engagement with an extension of the contact 14, whereupon the natural resilience of the contact structure 14 will cause this contact structure to rise from engagement with the contact 13 into engagement with a contact 15, with the result that the bridge circuitfor the relay 7 is broken at 13,.14 and a bridge circuit for the telephone receiver and transmitter established at 14, 15, this latter bridge circuit being traceable from the side 1 .of the telephone line through the contacts 5, 6, the contacts 16, 17, the transmitter 10, the receiver 9, the contacts 15 and 14, to the side 2 of the telephone line. The contacts 16 and 17 serve to shuntthe' magnet 11, which is of high resistance say 3,000 ohms, so as to exclude its resistance from If the line has been taken for use at some other station prior to the removalof the receiver at a line seeking station, such seeking station cannot secure connection with the line when previously appropriated (having in mind the normal connection of the battery with the line) owing to the fact that each relay 7 is desirably of very high resistance, say 15,000 ohms, while the normal telephone bridge that is established at any station is, of

course, of-low resistance, the low resistance bridge at the station already having con-- nection with the line serving to shunt, the vpassage of sufficient operating current from the relay 7 at the seeking station to preyent this relay from operating. The polarized relay 7 at such seeking station remaining inert, the contacts of the a mature switch 8 of such relay are not closed, the closure of these contacts being essential to the energization of the magnet ll. Which Assuming that one of energization is required to free the contact 14, so that the telephone bridge at the seeking station may be established there the battery is reversed the line is further guard: ed against intrusion since the relay 7 at the seeking station cannot respond to the reversed current. Thus a station seeking its line which is previously busy has its telephone locked out. The dial. contacts 5,- 6 at such a seeking station are also excluded from operative association with thetele-' phone inasmuch as these dial contacts are serially included in the telephone bridge, the

dial contacts and the-telephone receiver de pending for their connection with the telephone line .upon the contacts 14 and 15 common thereto and serially related therewith. Thus the-dial mechanism at a station seeking connection with its line that is pre viously busy cannot'b'e effectively operated to disturb the connection of the telephone line'with the extension thereof at the exchange.

that theassociate magnet 7 is excluded from bridge connection between the sides of the telephone line.

\Vhen a party line station is through with its use for the line, the telephone receiver thereat is restored upon its switch hook whereupon the lug 19 upon the switch hook actuated post 20 engages the contact structure 14 to cause it to escape and thereafter be engaged by the armature catch of the associate magnet 11, this magnet then 'hav-. ing its circuit opened at 14, 15' so that said armati re catch may be free to engage and hold tie contact 14 in its normal position.

Each contact structure 14 when free is adapted to press a flange 21 upwardly against the force of a spring 22 so that one who seeks appropriation of the party line will know that the line is free for selection or use, and that it is not free for use if the flange is not moved upwardly.

\Vhen a station is a called station, the calling station being upon some other telephone line, the connection of the battery 8 with the called telephone line is normal so that-the results which have been described are similar to the results which follow when. the station is a calling station. Y

. By the arrangement illustrated the polarized relay 7 performs a circuit opening and .closing function only, the locking out func- .tion being performed by-a distinct magnet 11 whose circuit is governed by the polarized relay 7.

I. will now describe the mechanism that is employed, when the invention is embodied in an automatic telephone exchange system, for reversing the battery-'3, when a station is a calling station, by particular reference to Fig. 3.

the stations, say

lVhen contacts 14 and 15 are engaged, contacts 13 and 14 are disengaged so nected with the side 2 station C, is a calling station, the party at such station will remove his telephone from its switch hook to include the relay 7 and magnet 11 in bridge of the party line in sequence as has been described.- Initially the negative pole of the battery 8 is conof the telephone line by way of a path which may be traced from the upper or negative pole of the battery 3 through the upper winding of the relay 23, the normal contact of the upper armature switch of relay 2-1, thisrelay then being inert, the normal contact of the upper armature switch of the relay 25, to the line side 9. Circuit for the battery 3 is completed by the connection established at the calling substation, the continuation of the circuit being traceable across the line side at the calling station to the side 1, the lower armature switch of the relay 25 and its normal contact,

vthe intermediate armature switch of relay 2t and its normal contact, the lower windmg of relay 23 to ground. The relay 23 is initially not adapted to respond asit is in circuit with one or the other of the high resistance bridges at the calling station that individually include the polarized relay 7 and the releasing magnet 11, so that during the presence of these high resistance bridges across the line at the calling station the bat tcry 3 still has its negative pole in normal connection with the line side 52. Vhen the telephone bridge is established in the manner which has been described, the current through the relay is sutliciently incr need to permit it to become etl'cctively energized whereby it causes the operation of its armature switch to move it from its normal con tact into engagement with its alternate contact thereby to establish a circuit which may be traced from this contact, which is grounded, through the armature switch the winding of relay 26 to the grounded battery 8. The armature switches of relay 90 are thereupon attracted and the upper armature switch closes circuit through relay Ql which may be traced from the upper grounded coni tact of relay 26, winding of relay 2t to the grounded battery 3. The armature switches of relay 2i are thereupon attracted and the upper and intermei'liate armature switches of this relay cause the connection of the battery 3 with the calling line to be reversed. the negative pole of this battery then being connected with the side l of the'telephone line by a path which may be traced from the negative pole of the battery through the upper winding of relay 23, the alternate contact of the intermediate armature switch of relay 24-, the normal contact of the lower armature switch of relay 25 to the side 1 of the ailing line, the side 2 of the'calling line being then directly connected with ground by way of a path which may be traced from the normal contact of the upper armature switch of relay 25 to the upper armature switch of relay 2t and its alternate contact, through the lower winding of relay 23, to ground. The positive pole of the battery it is thus connected with the line side 2. As

has been explained, the reversing of the connection of the battery 3 with the line sides prevents any other relay 7 upon the same party line from responding. it being necessary to restore the normal relation of the battery 3 with the line if the calling and called parties are upon the same l ne. Much other apparatus is illustrated in Fig. 3 which is not particularly concerned in the operations which have been described and which apparatus is so familiar to those skilled in the art of automatic telephony as to require no specific description.

Vhile I have herein shown and particularly described the preferred embodiment of my invention I do not wish to be limited to the precise details of construction and circuit arrangement shown as changes may readily be made without departing from the spirit of my invention.

Having thus described my invention I claim as new and desire to secure by Letters Patent the following:

1. A telephone exchange system including a party telephone line extending from a plurality of telephone stations to an exchange; n'iagnets at the party line stations serving normally to lock the telephones thereat out of circuit relation with the line; polarized relays at the telephone stations for establishing circuit through the aforesaid magnets to permit the association of the telephones with the line; a source of uni-directiomil current normally in such circuit relation with the line as to cause the energization of the polarized relays; switching devices at the stations for closing circuit through said relays and said source of current; and means a. the exchange for changing the direction of current flow to render the polarized relays un responsive t those use of the line.

2. A telephone exchange system including a party telephone line extending from a plurality of telephone stations to an exchange.

at which exchange mechanism is provided For automatically effecting extension of said telephone line: mechanism at the telephone stations for ettccting the operation of the line extending mechanism at the exchange; magnets at the party line stations serving normally to prevent the effective operation of the mechanism at the telephone stations that is employed to initiate the automatic extension of the line; relays at the telephone stations r'or establishing circuit through the aforesaid magnets to permit of the line extension at the exchange and means at the exchange for preventing and permitting of the energization of said relays.

being grounded stations that do not have iso 3. A telephone exchange system includ- -1ng a party telephone line extending from a plurality of telephone stations to an ex: change, at Which exchange mechanism is provided for automatically effecting extension of said telephone line; mechanism at 4 ate the automatic extension of the line;

polarized relays at the telephone stations for establishing circuit through the aforesaid magnets to permit of the line extension at the exchange; a source of uni-di rectional current normally in such circuit relation with the line as to cause the energization of the polarized relays; switching devices at the stations for closing circuit through said relays and said source of current; and means at the exchange for changing the direction of current flow to render the polarized relays unresponsive at those stations that do not have use of the line.

4. A telephone exchange system including a party telephone line extending from a plurality of telephone stations to an exchange; magnets at the party line stations serving normally to lock the telephones thercat out of circuit relation with the line; relays at the telephone stations for establishing circuit through the aforesaid magnets to permit the association of the telephones ivith the line; and means at the exchange for preventing and permitting the encrgization of said relays, there being apparatus at the party line stations for gov erning the latter means.

5. A telephone exchange system including a party telephone line extending from a plurality of telephone stations to an exchange; magnets at'the party line stations serving normally to lock the telephone thercat out of circuit relation with the line; polarized relays at the telephone stations for establishing circuit through the aforesaid magnets to permit the association of the telephones with the line; a source of uni-directional current normally in such circuit relation with the line as to cause the energization of the polarized relays; switching de vices at the stations for closing circuit through said relaysand saidsource'of current; and means at the exchange for changing the dircction of current flow to render the polarized relays unresponsive at those stations that do not have use of the line,

there being apparatus at the party line stations for governing the latter means.

6. A telephone exchange system includ ing a party telephone line extending from a plurality of telephone stations to an exchange, at which exchange mechanism is provided for automatically effecting eXtension of said telephone line; mechanism at the telephone stations for effecting the operation of the .line extending mechanismat the exchange; magnets at the party line stations serving normally to prevent the efi'ectiveoperation of the mechanism at the telephone stations that is employed to initiate the automatic extension of the line; relays at the telephone stations for establishing circuit through the aforesaid magnets to permit of the line extension at the exchange;

and means at the exchange for preventing and permitting of the energization of said relays, there being apparatus at the party line stations for governing the latter means.

7. A telephone exchange system including a party telephone line extending from a plurality of telephone stations to an exchange, at which exchange mechanism is provided for automatically efiecting extension of said telephone line; mechanism at the telephone stations for effecting the op eration of the line extending mechanism at the exchange; magnets at the party line stations serving normally to prevent the efl'ectire operation of the mechanism at the telephone stations that is employed to initiate the automatic extension. of the line; polarized relays at the telephone stations for establishing circuit through the aforesaid magnets to permit of the line extension at the exchange; a source of uni-directional current normally in such circuit relation with the line as to cause the energization of the polarized relays; switching devices at the stations for closing circuit through said relays and said source of current; and means at the exchange for changlng the direction of current flow to render the polarized relays unresponsive to those stations that do I not have use of the line, there being apparatus at the party line stations for governing the latter means.

' In witness whereof, I hereunto subscribe my name this 24th day of July, A. D, 1911.

MORTON L. JOHNSON.

{ opics of this patent may be obtained for five cents each, by addressing the Commissioner 0? Patents.

' Washington, D. C." 

